CHAP. XVIII. 



OF POTOSJ. 59 



pose that Potosi, in the earlier years of its working, 

 yielded much more than is here estimated ; but 

 whoever has paid much attention to the more an- 

 cient Spanish writers, especially when they speak 

 in round numbers, will receive their relations with 

 considerable hesitation. 



There are some considerations which would 

 lead to a doubt whether Potosi produced, in the 

 first ten years of its being worked, so large a 

 quantity of silver as in the years that followed 

 after 1556. The Indians, who had been com- 

 pelled to perform the labour, must have been 

 unaccustomed to it, and would require time to 

 gain the habit of working with effective expedition. 

 The method of extracting the silver by the pro- 

 cess of amalgamation had not been introduced, as 

 it was not discovered in Mexico, from whence it 

 was carried to Peru, till the year 1 557 > and the 

 mines of mercury in Guancavelica had not then 

 been opened, and till they were, the amalgamation 

 process could not have been used. As the miners 

 of Potosi could only obtain the silver by smelting, 

 and as fuel was not to be procured near the Cerro, 

 a difficulty would present itself which could not 

 be overcome so completely as it must afterwards 

 have been when the practice of amalgamation was 

 introduced. 



The feeling of confidence in Humboldt is so 

 much increased by every examination of his state- 

 ments, that any slight difference from his repre- 



